Circuit maker and breaker



March 11, 1930. H GRQH 1,750,517

CIRCUIT MAKER AND BREAKER Filed Oct. 18, 1926 Inzrsninr HarnldD 517011 Patented 11, 1930 UNITED STTE HAROLD DAVID GROI-I, OF TOR-ONTO, ONTAI-I-IG, CANADA CIRCUIT MAKER AND BREAKER Application filed October 18, 1926.

My invention relates to improvements in circuit makers and breakers, and the object of the invention is to devise a device of this type adapted for use either as a thermostat orpressure switch which is simple and cheap to manufacture, which will function without the employment of any mechanical means, in which there is no liability to corrosion, which will be positive and definite in operation, and

in which there are no parts liable to deteriorate and get out of order, and it consists essentially of the arrangement and construction of parts as hereinafter more particularly explained.

Figs. 1, 2 and 3 illustrate one embodiment of my invention in which the liquid for genera-ting the vapor pressure is separated from the mercury by a thin wall, Figure 1 being a section elevation parallel with the face of the device, Figure 2 a transverse section through Figure 1, and Figure 3 a transverse section showing a modification of the structure illus trated in Figures 1 and 2.

Fig. 1 is a sectional view through an alternative form showing the bellows construction illustrated in Figures 1 and 2 in double form.

In the drawings like characters of reference indicate corresponding parts in each figure.

Referring first to Figures 1 and 2.

This construction consists of a casing formed by two members 24 and 25 suitably secured together to form a chamber 26 containing a body of mercury 27. The chamber 26 is provided with a neck 26 into which is secured a glass tube 28 having an enlargement 29 at its upper end forming a gas containing chamber into which the body of mercury 27 extends. Within the chamber 26 is located a bellows 30 of thin flexible metal containing liquid adapted to be converted into vapor by a rise in temperature. As the temperature rises the vapor expands expanding the bellows 30 so as to force the mercury into the chamber 29, such chamber being provided with a cupped recess 29* and barrier 31, the cupped recess containing a body of mercury 32, 33 and 34 being the circuit terminals entering respectively the bodies of mercury 27 and 32, the circuit being closed as above illus- Serial No. $2,449.

trated by vapor pressure in the bellows 30 forcing the mercury into the chamber 29 so that the main body of mercury 26 overflows the barrier 31 to merge with the body of mercury 32.

In Figure 3 I show a construction similar to the Figures 1 and 2 with the exception that instead of the bellows construction 30 illustrated in these figures I have divided the chamber 26 by a flexible diaphragm 35 separating the body of mercury 36 from the pressure fluid 37.

The liquid with its vapor giving the operating pressure may be interchanged with the counteracting gas in the lateral extension to give an instrument which opens the circuit with a rise of pressure and temperature.

If it is desired to keep the liquid away from the surface of the mercury where the electric contact is made another bellows 38 may be employed as illustrated in Figure 4 and containing the pressure liquid 39. This bellows may be placed above the level of the mercury 10 and connected to the bellows 4:1 by a connector 4:2 in such a way that when the upper bellows expands due to increased pressure therein the lower bellows is forced downward and therefore to contract and thus lower the mercury in the tube 43 terminating in a chamber 14 similar in construction to that illus trated in the previous figures.

In all the foregoing illustrations the bellows or diaphragm is built as light and flexible as is mechanically advisable so that the resistance it offers to a change in the pressure is negligible. The change of pressure is preferably counteracted by a change in volume of gas or by change in height of the column of mercury or by both.

To adjust the devices for other than thermostat use it is only necessary to eliminate the liquid which generates the pressure from the chamber or bellows and make a suitable opening in the said chamber or bellows to which a pipe may be fitted leading to the pressure by which it is desired to operate.

From this description it will be seen that I have devised a very simple form of circuit maker or breaker which may be used as either a thermostat or switch and is operated entirely by fluid pressure, and thereby eliminating the use of mechanical means for operating the device for raising and lowering the mercury level and thereby obviating any danger of the device becoming out of order or the parts corroding or deteriorating in any way, and atthe same time providing a device which is definite and positive in operation and which is simple and cheap to manufacture.

What I claim as my invention is:

1. A circuit maker and breaker comprising a duct containing a column of mercury, a member provided with a cupped recess adapted to contain mercury and r orm a barrier wall between said mercury and the mercury of the duct, and an expansible vapor subject to temperature changes to exert pressure upon the'mercury body to raise or lower the level thereof above or below the barrier wall to make or break contact with the'mercury contained in the cupped recess, and a thin resilient wall interposed between the body of mercury forming the mercury column and the eXpansible fluid. V

2. A circuit maker and breaker comprising a vessel containing a body of mercury having a lateral extension forming a chamber and depressed at its outer end to form a mercury containing cupped recess, and a barrier wall interposed between the cupped recess and the main body of mercury, circuit terminals entering respectively the main body of mercury and the mercury of the cupped recess, a thin walled resilient bellows adapted to contain vapor pressure to eXert pressure upon the main body of mercury to change the level thereof above and below the level of the barrier wall.

3. A circuit maker and breaker comprising a vessel containing a body of mercury having a lateral extension forming a chamber and depressed at its outer end to form a mercury containing cupped recess, and a barrier wall interposed between the cupped recess and the main body of mercury, circuit terminals entering respectively the main body of mercury and the mercury of the cupped recess, a thin walled resilient bellows submerged in the main body of mercury and containing an we pansive fluid to oppose a change in mercury level, a correspondingly formed bellows contained in the vessel above the mercury level and adapted to contain vapor pressure sub-- ect to temperature changes, and a connector between the bellows;

i. A; circuit maker and breaker comprising upper wall and falls with a higher pressure.

HAROLD DAVID GROH. 

